Flat beer is the scourge of beer drinkers, homebrewers, craft brewers and beer corporations alike. No one likes a flat-tasting beer.
The flavor of each brand is one of its most relevant quality standards. Depending on the beer type and its storage conditions, changes in the chemical composition produced during its creation can affect its taste. Unlike with wines, those effect can negatively affect the quality of the flavor.
Blame oxidation for the trouble. Prolonged exposure to oxygen can give beer what the brewing world calls an “off flavor,” a taste described like cardboard. The chemical compound that appears when beer ages and acquires that stale taste is called furfural, which sounds like it would taste, cardboard-y. But furfural doesn’t give beer that unsatisfying flavor, but its appearance correlates with it.
Now, a team of chemists has developed a method that allows brewers to measure the freshness of beer, using a polymer sensor that changes color when it detects furfural. And, if you already didn’t have enough apps on your phone, the team created one that allows you to control the sensor from your smartphone. So, you could be out enjoying somewhere a beer while monitoring your own brew elsewhere. Hypothetically speaking, of course.
The results of the study have been published in the journal Analytical Chemistry.
The team of researchers, which hails from the Complutense University of Madrid (UCM), created sensor discs made from a polymer similar to the one used to make contact lenses. The sensors not only change color when in the presence of furfural, but also their precise shade of color corresponds with the amount of furfural detected.
Researcher Elena-Benito-Peña explains that brewers typically have measured furfural and other freshness indicators using methods based on chromatography techniques.
"But these methods involve the use of expensive equipment and sample preparation is very time-consuming," she says. "We’ve incorporated an aniline derivative into the sensor material which reacts with the furfural and produces a pink cyanine derivative that allows us to identify the presence of the marker in the sample. The intensity of the color increases as the concentration of furfural in the beer rises and, thus, as more time passes since the beer was produced.”
The team also created a mobile app for Android smartphones that, by taking a picture of the sensor disc, allows for the identification of the amount of furfural present in the beer. With this data, the degree of freshness can be determined.
The application is available as open source, meaning that any programmer can utilize and modify it to be used on other platforms. In the future it will also be available for Apple IOS.
RESULTS COMPARABLE TO MORE SOPHISTICATED METHODS
Benito-Peña recounts that the idea of developing the new method came about following a meeting with Mahou-San Miguel in which the Spanish brewer spoke about the technical difficulties it was having in detecting furfural directly at the production facilities.
The results of the tests on the new system "have been very satisfactory," Benito-Peña tells The Information and Scientific News Service (SINC). “The measurements have been taken using samples sent directly from the brewing company with different production dates and distinct degrees of aging. These same samples were also sent to a laboratory where they were analyzed using gas chromatography coupled with mass spectrometry. The results we obtained were completely comparable.”
The method was initially developed for brewing companies. "Especially, because the global market for this product is huge. But it can also be used with other food products such as honey, milk, coffee, etc.” she says.
For beer lovers, that sounds like something to celebrate by hoisting a pint of their favorite brew.